Researchers Find Million-Year-Old Stegodon Skull

November 24, 2015 |
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Researchers recently discovered a massive, fossilized skull of a prehistoric elephant at an excavation site in Gujrat, Pakistan

Scientists pinpointed the skull to be 1.1 million years of age, and the size and structure of the skull – nearly a foot wide and just over a foot long – to that of a prehistoric, female Stegodon

Stegodons are from the Proboscidean order of elephants, so named because of their prominent nose, and related to numerous related species that have gone extinct over millennia, such as the Deinotheriidae, also from the Pleistocene Epoch

Numerous animal fossils have been recovered from all over the globe, many of them prehistoric elephants found in the Great Lakes Region, as well as other animals such as the extinct saber-toothed cat and T. rex

By Dr. Becker

A team of researchers from the Zoology Department of Punjab University in northeastern Pakistan recently discovered a massive, fossilized skull during routine excavation in the Panjan Sher Shahana Hills area near the city of Gujrat, Pakistan. The team had been working in the area for a year and a half.

It took almost two days for the group, led by Professor Syed Ghayoor Abbas, to unearth the skull without causing further defects because of its size – a weighty 265 pounds. Part of the left tusk was broken off and the ventral (under side) was minimally damaged, but the back appeared to be intact, Abbas said.

Scientists in a hydrocarbon lab identified the structure of the skull as that of a 1.1-million-year-old Stegodon elephant, approximately twice the size of today’s extant elephants and closely related to a Wooly Mammoth. Its smaller-sized tusks indicated it belonged to a female specimen, and was similar to ancient remains found in Africa, Europe, and Asia.

Abbas and the research team hope the fossilized skull will provide more information about how Stegodons, which means “roofed tooth,” morphed over millennia to more closely resemble present-day elephants.

Stegodons – Not Just Another Elephant

Paleontologists believe the first elephant species appeared on the African continent and remained through the Paleocene Epoch, which, according to Encyclopedia Britannica,1 fell between 66 million and 56 million years ago. The Gomphotheriidae, from which Stegodons are thought to have evolved over millenia, were the first Proboscideans to look like the elephants we see today.

The Proboscideans, named because their flexible, muscular trunk was its most prominent feature, comprises:

“… Any group of mammals that includes elephants and their extinct relatives such as mammoths and mastodons. Although only three species of elephantare extant today, more than 160 extinct proboscidean species have been identified from remains found on all continents except Australia and Antarctica.”2

Elephants, of course, still exist, while a number of Proboscideans, like the Stegodon and its predecessor, the Stegolophodon, are now extinct. Scientists place numerous, loosely related Proboscideans with elephant-like characteristics in the Oligocene era, which occurred 65.5 million to 23 million years ago.

Examples are the Numidotheriidae and Barytheriidae, both from the Eocene-Oligocene Epochs, and the Deinotheriidae, a species whose plentiful remains have been found in Europe and Turkey,3 died out relatively recently in the Pleistocene Epoch – aka the latest Ice Age – which ended about 11,700 years ago.4

Stegodons, roaming throughout Europe, Africa, and Asia, sought forested areas to live. They’re described as having low, crowned teeth with peaked ridges and long, straight tusks, which scientists say indicates they must have been browsers or “mixed feeders.”5 However, according to Earth Sciences Museum, the Stegodon:

“… [M]ust have been a good swimmer because (its) fossils are frequently encountered on Asian islands, which even during periods of low sea-level were not connected by land bridges with the Asian continent.”6

The University of California Museum of Paleontology says Stegodons may have belonged to the larger Elephantidae group:

“(Stegodons) most likely originated during the Pliocene in South China based on the high diversity of this genus in the area, however there is a reported record of the genus from Kenya, Africa dated at 6.5 million years ago. From South China, Stegodon rapidly diversified and spread through Asia. They were able to swim and reached many islands in southeastern Asia (even islands that were not connected during low sea levels of glaciation periods). Stegodondiversified on the Japan islands resulting in several endemic species.”7

A ‘Dearth’ of Information on Prehistoric Specimens

In just the last year, Abbas has discovered several fossils in the Gujrat area, which is an international tourist site. Most of the finds were of pigs, rhinos, and deer, and averaging around 20,000 years old, but the Stegodon skull is the first prehistoric fossil found in the area.

The large number of animal fossils there no doubt is because Gujrat is located between two major rivers, the Jhelum and the Chenab, and animals must have often migrated there.

“There is a dearth of research on animal remains in this site,” Abbas said – meaning there’s a serious shortage of ancient specimens and information available on them. He said he plans to return to the area with a team to continue excavating the area. His plan is to use the experience to write the thesis for his Ph.D.

The prehistoric animal skull measured nearly a foot wide and 14 inches long, an indication that Stegodons were roughly twice the size of today’s average adult elephant.

Dhok Sar, fewer than five miles from Panjan, has a history of yielding prehistoric animal fossils. In fact, they’re so plentiful that a local told Abbas that he’d first noticed a palate, the bony plate on the roof of the mouth of a skull, in the same geographical area at least 40 years earlier, and Abbas found it still there.

It turned out to be from an Elephas, a prehistoric Asian elephant variant closer to that of a present-day elephant.

For now, the skull resides at Punjab University’s Jhelum Campus, where officials plan to form a new fossil display and research center.

Prehistoric Elephant Remains Found on Multiple Continents

Stegodons, mammoths, and other prehistoric elephants have been discovered, many of them originating from a period that predates the separation of the American and European continents. The Paleobiology Research Group reiterates how widely Stegodons traveled, which explains why remains have been found in so many areas:

“Stegolophodon, a primitive example of the stegodontidae known from Japan, possessed tusks on both upper and lower jaws. The more recent Stegodon lost the lower tusks, and indeed lower incisor teeth altogether… Fossils of Stegodontids are found from the upper Miocene until the Pleistocene Epochs. The Stegodontidae mostly occur in Asia, although genera returned to Africa several times.”8

Remains of a Stegodon were found in an archaeological site on the Indonesian Island of Flores, but these belonged to a somewhat controversial dwarf subspecies, the youngest ever found, incidentally, called Stegodon florensis insularis.

“The assemblage from Liang Bua comprises mostly dental and skeletal elements of juvenile individuals. S.f. insularis is characterized by an advanced molar ridge formula and diminutive size: on average the molars are 30 per cent smaller in linear dimensions as compared to the ancestral species.”9

Along with other animal remains, the bones of one adult Stegodon and numerous baby Stegodons, along with rhino skeletons, were found in the Panxian Dadong Cave in Southern China in 1998, but Stegodons weren’t known to live in caves. Scientists speculate that carnivores – maybe even wolves – might have attacked and killed them, then dragged them there. However, evidence indicates that humans probably had a hand in the mystery:

"Clearly humans are doing something with the bones, because we're finding them burnt… There are cut marks. We found a beautiful example of a percussion damage mark where the bone had been pounded, probably by a stone tool. The same piece has a cut mark and was burnt. Everything you could do as a prehistoric person to damage a bone has been done."10

The bones were analyzed by a chemist at the University of Cincinnati Department of Environmental Health, and the Chinese government designated the cave a national preservation site, which is a rare occurrence.

A plethora of prehistoric creatures’ bones have been discovered in North America, East Asia, and Central Africa in fairly modern times. In fact, ancient remains from the Wooly Mammoth have been found in nearly every one of the 92 counties in Indiana, as well as in Michigan, Ohio, and other neighboring states. They’re so plentiful that it’s even possible to purchase tusks, teeth, and “arm” bones from the mammoth.11 Skeletons from other primordial animals have also been discovered, such as saber-toothed cats, dire wolves, and giant sloths.12

In 2006, the 400,000-year-old fossilized remains of a Palaeoloxodon antiquus, or straight-tusked elephant, were found near London.13

One of the most celebrated and fascinating skeletal discoveries was that of a Tyrannosaurus Rex, unearthed in 1990 in South Dakota, and thought to be the best preserved and most complete ever found. Now displayed in the Field Museum of Natural History in Chicago (and made famous through its cameo appearance for the film Jurassic Park) it’s dated to 67 million to 65 million years of age, from near the end of the Mesozoic Era. It’s one of around fifty Tyrannosaurus’ skeletons discovered, including more than one in Montana.14